Characterisation of the protolytic properties of synthetic carbonate free fluorapatite

A solubility and surface complexation study of a non-stoichiometric hydroxyapatite

“…Ishikawa et al (2000) have in fact provided compelling evidence for the presence of protonated surface phosphate groups on HAP particles that are similar in composition and specific surface area to the one used in this study. The findings of protonated phosphate groups on the HAP surface as a function of pH is in very good agreement with the findings of protonated surface phosphate groups from the 31 P MAS NMR measurements by Jarlbring et al (2005) which is discussed in Section 2.2.…”

“…These values can be compared with values obtained from alkalimetric titrations of synthetic carbonate-free FAP by Jarlbring et al (2005). They found N s to be 2.95 sites/nm 2 of phosphate and 2.34 sites/nm 2 of calcium in ionic strengths of 0.1 and 0.5 mol/dm 3 NaNO 3 .…”

“…31 P MAS NMR studies on hydroxy-and fluorapatite (FAP) have shown the presence of different protonated phosphate sites (Jarlbring et al, 2005). Jarlbring et al (2005) characterized the active phosphorous surface sites as well as bulk phosphate of fluorapatite using single pulse 1 H, 31 P, and 31 P MAS NMR. The surface sites were defined as "PO x , "PO x H, and "PO x H 2 with x = 1, 2, or 3 (charges omitted).…”

“…Their calculations were only based on crystallographic data with a total value of N s = 12.3 sites/nm 2 . As the numbers of sites based on the radioisotope measurements by Kukura et al (1972) are in close agreement with those of Jarlbring et al (2005) and Perrone et al (2002) they were chosen for the model calculations of this study.…”

Superficial acid-base properties of polymer fibres

“…As a rule, protolytic properties of PFM superficial sites are bland so it is necessary to use non-aqueous media for its studying [10,11]. Investigation of protolytic properties of fibres surface, as well as nature and a number of active sites, is necessary for realising the adsorptive capacity and selectivity of PFM.…”